Search for the flavor-changing neutral-current decay t→Zq in pp̄ collisions at s=1.96TeV

Physical Review Letters 101:19 (2008)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzurri, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, P Bednar, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, J Beringer, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, A Clark, D Clark, G Compostella

Abstract:

We report a search for the flavor-changing neutral-current decay of the top quark t→Zq (q=u, c) in pp̄ collisions at s=1.96TeV using a data sample corresponding to an integrated luminosity of 1.9fb-1 collected by the CDF II detector. This decay is strongly suppressed in the standard model and an observation of a signal at the Fermilab Tevatron would be an indication of physics beyond the standard model. Using Z+4 jet final state candidate events, with and without an identified bottom quark jet, we obtain an upper limit of B(t→Zq)<3.7% at 95% C.L. © 2008 The American Physical Society.

Top Quark Mass Measurement in the tt-bar All Hadronic Channel using a Matrix Element Technique in ppbar Collisions at sqrt s = 1.96 TeV

ArXiv 0811.1062 (2008)

Authors:

CDF Collaboration, T Aaltonen

Measurement of W-Boson Helicity Fractions in Top-Quark Decays Using costheta*

ArXiv 0811.0344 (2008)

Observation of Υ(2S)→ηΥ(1S) and search for related transitions

Physical Review Letters 101:19 (2008)

Authors:

Q He, J Insler, H Muramatsu, CS Park, EH Thorndike, F Yang, M Artuso, S Blusk, S Khalil, J Li, R Mountain, S Nisar, K Randrianarivony, N Sultana, T Skwarnicki, S Stone, JC Wang, LM Zhang, G Bonvicini, D Cinabro, M Dubrovin, A Lincoln, P Naik, J Rademacker, DM Asner, KW Edwards, J Reed, RA Briere, T Ferguson, G Tatishvili, H Vogel, ME Watkins, JL Rosner, JP Alexander, DG Cassel, JE Duboscq, R Ehrlich, L Fields, RS Galik, L Gibbons, R Gray, SW Gray, DL Hartill, BK Heltsley, D Hertz, JM Hunt, J Kandaswamy, DL Kreinick, VE Kuznetsov, J Ledoux, H Mahlke-Krüger, D Mohapatra, PUE Onyisi, JR Patterson, D Peterson, D Riley, A Ryd, AJ Sadoff, X Shi, S Stroiney, WM Sun, T Wilksen, SB Athar, R Patel, J Yelton, P Rubin, BI Eisenstein, I Karliner, S Mehrabyan, N Lowrey, M Selen, EJ White, J Wiss, RE Mitchell, MR Shepherd, D Besson, TK Pedlar, JV Xavier, D Cronin-Hennessy, KY Gao, J Hietala, Y Kubota, T Klein, BW Lang, R Poling, AW Scott, P Zweber, S Dobbs, Z Metreveli, KK Seth, A Tomaradze, J Libby, L Martin, A Powell, G Wilkinson, KM Ecklund, W Love, V Savinov, H Mendez, JY Ge

Abstract:

We report the first observation of Υ(2S)→ηΥ(1S), with a branching fraction B=(2.1-0.6+0.7(stat)±0.3(syst))×10-4 and a statistical significance 5.3σ. Data were acquired with the CLEO III detector at the CESR e+e- symmetric collider. This is the first process observed involving a b-quark spin flip. For related transitions, 90% confidence limits in units of 10-4 are B(Υ(2S)→π0Υ(1S))<1.8, B(Υ(3S)→ηΥ(1S))<1.8, B(Υ(3S)→π0Υ(1S)) <0.7, and B(Υ(3S)→π0Υ(2S))<5.1. © 2008 The American Physical Society.

A search for high-mass resonances decaying to dimuons at CDF

ArXiv 0811.0053 (2008)